Definition
This idiom suggests that in the contexts of romantic relationships and warfare, normal ethical or moral rules of conduct do not apply, and any actions are permissible to achieve one's goals.
在爱情和战争中，为了达到目的可以不择手段。
They were using every possible tactic to win the client, but as they say, all's fair in love and war.
他们用尽一切可能的策略来赢得客户，但正如他们所说，在爱情和战争中，为了达到目的可以不择手段。
He deceived his friends while pursuing her, but he figured all's fair in love and war.
他在追求她时欺骗了他的朋友，但他认为在爱情和战争中，为了达到目的可以不择手段。
When it came to getting promoted at work, she played very hard, because she believed all's fair in love and war.
当涉及到工作晋升时，她非常努力地竞争，因为她相信在爱情和战争中，为了达到目的可以不择手段。